Mitral valve treatment techniques

ABSTRACT

A method is provided for treating mitral valve regurgitation, including inserting a band around between 90 and 270 degrees of a mitral valve of a heart, including around at least a portion of a posterior cusp of the valve, in a space defined by (a) a ventricular wall, (b) a ventricular surface of the posterior cusp in a vicinity of an annulus of the valve, and (c) a plurality of chordae tendineae of one or more types of chordae tendineae selected from the group consisting of: second-order chordae tendineae and third-order chordae tendineae. The method also includes applying pressure to the posterior cusp by inflating the band.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims the benefit of: (a) U.S. ProvisionalPatent Application 60/662,616 to Gross et al., filed Mar. 17, 2005, and(b) U.S. Provisional Patent Application 60/700,542 to Gross et al.,filed Jul. 18, 2005. Both of these applications are assigned to theassignee of the present application and are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates generally to surgical methods andapparatus, and specifically to methods and apparatus for mitral valvetreatment.

BACKGROUND OF THE INVENTION

Mitral valve regurgitation is a disorder in which the mitral valve doesnot close properly. During systole, a healthy mitral valve preventsoxygenated blood from flowing back (regurgitating) from the leftventricle to the left atrium. Regurgitation caused by a defective mitralvalve reduces cardiac output, increasing the risk of progressive heartfailure. Treatments for mitral valve regurgitation include valvereplacement and strengthening the valve annulus by implanting amechanical support ring or other structure (generally called valveannuloplasty).

The chordae tendineae are commonly classified according to theirinsertion sites on the mitral cusps. The first-order (also calledprimary or marginal) chordae insert on the cusp free edges, thesecond-order (also called “strut”) chordae insert on the ventricularsurface of the cusps, usually near the junction between the rough andsmooth zones, and the third-order (also called tertiary or basal)chordae originate directly from the trabeculae cameae of the leftventricular wall, and attach to the cusps near the annulus of the mitralvalve.

US Patent Application Publication 2005/0010287 to Macoviak et al., whichis incorporated herein by reference, describes techniques forsupplementing, repairing, or replacing a native heart valve. Thetechniques employ an implant that is adapted to extend adjacent a valveannulus. The implant includes a mobile neoleaflet element that occupiesthe space of at least a portion of one native valve leaflet. The implantmimics the one-way valve function of a native leaflet, to resist orprevent retrograde flow. The implant restores normal coaptation of theleaflets to resist retrograde flow, thereby resisting eversion and/orprolaspe, which, in turn, reduces regurgitation.

US Patent Application Publication 2004/0193191 to Starksen et al., whichis incorporated herein by reference, describes methods for treating acardiac valve annulus, comprising contacting an anchor delivery devicewith the valve annulus and releasing a plurality of coupled anchors fromthe anchor delivery device to secure the anchors to the annulus.Anchors, which in some embodiments are super-elastic or shape memoryself-securing anchors, are then drawn together to tighten the annulus.The publication also describes devices including an elongate catheterhaving a housing at or near the distal end for releasably housing aplurality of coupled anchors. The housing may be flexible, may conformto a valve annulus, and in some embodiments may be coupled with anexpandable member to enhance contact of the housing with annular tissue.In one embodiment, self-securing anchors lie approximately flat withinthe delivery device housing, allowing anchors with relatively largedeployed shapes to be housed in and deployed from a relatively narrowdelivery device.

US Patent Application Publication 2004/0148020 to Vidlund et al., whichis incorporated herein by reference, describes techniques for improvingthe function of a valve (e.g., a mitral valve) by positioning animplantable device outside and adjacent the heart wall such that thedevice alters the shape of the heart wall acting on the valve. Theimplantable device may alter the shape of the heart wall acting on thevalve by applying an inward force and/or by circumferential shortening(cinching). The shape change of the heart wall acting on the valve issufficient to change the function of the valve, and may increasecoaptation of the leaflets, for example, to reduce regurgitation.

US Patent Application Publication 2004/0148019 to Vidlund et al., whichis incorporated herein by reference, describes techniques for improvingthe function of a valve (e.g., a mitral valve) by positioning a spacingfilling device outside and adjacent the heart wall such that the deviceapplies an inward force against the heart wall acting on the valve. Asubstantially equal and opposite force may be provided by securing thedevice to the heart wall, and/or a substantially equal and oppositeoutward force may be applied against anatomical structure outside theheart wall. The inward force is sufficient to change the function of thevalve, and may increase coaptation of the leaflets, for example. Thespace filling device may be implanted by a surgical approach, atransthoracic approach, or a transluminal approach, for example. Thespace filling portion may be delivered utilizing a delivery catheternavigated via the selected approach, and the space filling portion maybe expandable between a smaller delivery configuration and a largerdeployed configuration.

US Patent Application Publication 2004/0138745 to Macoviak et al., whichis incorporated herein by reference, describes medical devices forimproving heart valve function, including leaflet retainers, aneo-annulus, neo-leaflet, and a framework.

US Patent Application Publication 2004/012983 to Mortier et al., whichis incorporated herein by reference, describes a device for heart valverepair including at least one tension member having a first end andsecond end. A basal anchor is disposed at the first end of the tensionmember and a secondary anchor at the second end. The publicationdescribes a method including the steps of anchoring the basal anchorproximate a heart valve and anchoring the secondary anchor at a locationspaced from the valve such that the chamber geometry is altered toreduce heart wall tension and/or stress on the valve leaflets.

U.S. Pat. No. 6,629,534 and US Patent Application Publication2004/0039442 to St. Goar et al., which are incorporated herein byreference, describe techniques for performing endovascular repair ofatrioventricular and other cardiac valves in the heart. Regurgitation ofan atrioventricular valve, particularly a mitral valve, is repaired bymodifying a tissue structure selected from the valve leaflets, the valveannulus, the valve chordae, and the papillary muscles. These structuresare modified by suturing, stapling, snaring, or shortening, usinginterventional tools which are introduced to a heart chamber.

US Patent Application Publication 2003/019974 to Lee et al., which isincorporated herein by reference, describes an annuloplasty system forrepairing a heart valve, comprising a surgical implant including amember having first and second end portions. The implant member furtheris configured and/or adapted to form a partial ring along a portion ofone of the valve annulae of a patient's heart such as the mitral ortricuspid valve annulus. The implant member is axially elastic such thatit can axially expand and contract and includes first and second anchorsextending from the end portions of the implant member. The anchors areadapted to anchor the implant in tissue such as the mitral or tricuspidvalve annulus. The system is described as facilitating tissue plication(e.g., of the posterior annulus of the mitral valve or the annulus ofthe tricuspid valve) and reinforcement of a valve annulus.

US Patent Application Publication 2003/0191528 to Quijano et al., whichis incorporated herein by reference, describes an expandable annularring for implantation in a valvular annulus and its percutaneous use.The ring comprises a plurality of stenting elements made of a firstshape-memory material having a first shape-transition temperature,wherein the first shape-memory material expands to a preshape when thefirst shape-memory material is heated to above the firstshape-transition temperature; and a plurality of anchoring elements madeof a second shape-memory material having a second shape-transitiontemperature that is higher than the first shape-transition temperature,wherein the second shape-memory material expands to the second preshapewhen the second shape-memory material is heated to above the secondshape-transition temperature.

US Patent Application Publications 2004/0260393 to Rahdert et al. and2004/0127982 to Machold et al., which are incorporated herein byreference, describe techniques using an implant that is sized andconfigured to attach in, on, or near the annulus of a dysfunctionalheart valve. In use, the implant extends either across the minor axis ofthe annulus, or across the major axis of the annulus, or both. Theimplant is described as restoring to the heart valve annulus andleaflets a more functional anatomic shape and tension. The morefunctional anatomic shape and tension are conducive to coaptation of theleaflets, which, in turn, reduces retrograde flow or regurgitation.

US Patent Application Publication 2004/0260394 to Douk et al., which isincorporated herein by reference, describes a cardiac valve annuluscompressor comprising a generally cylindrical main body having plain andbarbed ends and an actuator portion. Barbs disposed on the barbed endare engageable with the valve annulus. The length of the circumferenceof the barbed end is responsive to movement of the actuator portion. Theannulus compressor can be delivered percutaneously or surgically.

US Patent Application Publication 2004/0236419 to Milo, which isincorporated herein by reference, describes methods for reconfiguring anatrioventricular heart valve that use systems comprising a partial orcomplete annuloplasty rings proportioned to reconfigure a heart valvethat has become in some way incompetent, a pair of trigonal sutures orimplantable anchors, and a plurality of staples which may have pairs oflegs that are sized and shaped for association with the ring at spacedlocations along its length. These systems are described as permittingrelative axial movement between the staples and the ring, whereby apatient's heart valve can be reconfigured in a manner that does notdeter subtle shifting of the native valve components. Shape-memory alloymaterial staples may have legs with free ends that interlock followingimplantation. Annuloplasty rings may be complete or partial and may befenestrated. One alternative method routes a flexible wire, preferablyof shape-memory material, through the bights of pre-implanted staples.Other alternative systems use linkers of shape-memory material havinghooked ends to interengage with staples or other implanted supportswhich, following implantation, decrease in effective length and pull thestaples or other supports toward one another so as to create desiredcurvature of the reconfigured valve. These linkers may be separate fromthe supports or may be integral with them and may have a variety ofshapes and forms. Various of these systems may be implantednon-invasively using a delivery catheter.

US Patent Application Publication 2004/0243227 to Starksen et al., whichis incorporated herein by reference, describes techniques forfacilitating positioning of a cardiac valve annulus treatment device.The publication describes methods including advancing an anchor deliverydevice through vasculature of the patient to a location in the heart fortreating the valve annulus, contacting the anchor delivery device with alength of the valve annulus, delivering a plurality of coupled anchorsfrom the anchor delivery device to secure the anchors to the annulus,and drawing the anchors together to circumferentially tighten the valveannulus. Devices generally include an elongate catheter having at leastone tensioning member and at least one tensioning actuator for deforminga distal portion of the catheter to help it conform to a valve annulus.The catheter device may be used to navigate a subannular space below amitral valve to facilitate positioning of an anchor delivery device.

Odell J A et al., in an article entitled “Early Results of a SimplifiedMethod of Mitral Valve Annuloplasty,” Circulation 92:150-154 (1995),which is incorporated herein by reference, studied the outcome of threedifferent annuloplasty techniques: commissural annuloplasty, completering annuloplasty, and an unmeasured, posterior, partial ringannuloplasty. They concluded that postoperative valve function obtainedby unmeasured posterior annuloplasty, as assessed by degree ofregurgitation, transvalvular gradient, and valve area, was similar tothat obtained by measured, complete ring annuloplasty and superior tothat found in patients having commissural annuloplasty.

US Patent Application Publication 2003/0078465 to Pai et al., which isincorporated herein by reference, describes techniques for testingdegenerative, congestive heart disease and related valvular dysfunction.Percutaneous and minimally invasive surgical tensioning structures areimplantable within various major coronary blood-carrying conduitstructures (arteries, veins and branching vessels), into or throughmyocardium, or into engagement with other anatomic structures thatimpact cardiac output to provide tensile support to the heart musclewall which resists diastolic filling pressure while simultaneouslyproviding a compressive force to the muscle wall to limit, compensate orprovide therapeutic treatment for congestive heart failure and/or toreverse the remodeling that produces an enlarged heart. In someembodiments, the tensioning structures are used to apply tension topapillary muscles and/or chordae tendineae to reposition the valveleaflets to reduce/eliminate regurgitation, to limit the motion of theleaflets to improve/restore the function of cardiac valves; and todirectly reposition the valve leaflets to prevent prolapse or otherabnormalities of the leaflets and to prevent associated deficiencies.

US Patent Application Publication 2003/0018358 to Saadat, which isincorporated herein by reference, describes techniques for thermallyand/or mechanically treating tissue, such as valvular structures, toreconfigure or shrink the tissue in a controlled manner. Mechanicalclips are implanted over the leaflets of a valve, e.g., in the heart,either alone or after thermal treatment to cause the valve to close moretightly. The clips are delivered by a catheter and may be configured totraverse directly over the valve itself or to lie partially over theperiphery of the valve to prevent obstruction of the valve. channel.Alternatively, individual anchors with a tensioning element, like asuture, are described as being useful for approximating the valvestowards each other.

U.S. Pat. No. 6,626,899 to Houser et al., which is incorporated hereinby reference, describes techniques for thermally and/or mechanicallytreating tissue, such as valvular structures, to reconfigure or shrinkthe tissue in a controlled manner. The apparatus comprises a catheter incommunication with an end effector which induces a temperature rise inan annulus of tissue surrounding the leaflets of a valve or in thechordae tendineae sufficient to cause shrinkage, thereby causing thevalves to close more tightly. Mechanical clips can also be implantedover the valve either alone or after the thermal treatment. The clipsare delivered by a catheter and may be configured to traverse directlyover the valve itself or to lie partially over the periphery of thevalve to prevent obstruction of the valve channel.

US Patent Application Publication 2005/0222678 to Lashinski et al.,which is incorporated herein by reference, describes methods and devicesfor applying pressure to an adjacent tissue structure, such as theannulus of the mitral valve. An adjustable implant is described with anelongate control line having a distal end connected to the implant and aproximal end spaced apart from the implant. The device enables postimplantation adjustment, by accessing the proximal end of the controlline and manipulating the control line to adjust the implant.

US Patent Application Publication 2005/0096740 to Langberg et al., whichis incorporated herein by reference, describes a mitral annuloplasty andleft ventricle restriction device adapted to be transvenously advancedand deployed within the coronary sinus and, in some embodiments, othercoronary veins. The device places tension on adjacent structures,reducing the diameter and/or limiting expansion of the mitral annulusand/or limiting diastolic expansion of the left ventricle. These effectsmay be beneficial for patients with dilated cardiomyopathy.

SUMMARY OF THE INVENTION

In some embodiments of the present invention, a mitral valve treatmentdevice comprises a band, a distal coupling element, and a proximalcoupling element. The device is adapted to be placed around between 90and 270 degrees of a mitral valve, including around at least a portionof a posterior cusp of the valve, in a space defined by (a) aventricular wall, (b) a ventricular surface of the posterior cusp in avicinity of an annulus of the mitral valve, and (c) a plurality ofthird-order chordae tendineae. The proximal and distal coupling elementsare adapted to be coupled to a first chorda tendinea and a second chordatendinea, respectively, each of the first and second chordae tendineaeselected from the group consisting of: one of the plurality ofthird-order chordae tendineae, and a first-order chorda tendinea thatinserts on a commissural cusp of the mitral valve. Such couplingtypically tightens the annulus and thereby treats mitral valveregurgitation. Alternatively or additionally, the space is defined by aplurality of second-order chordae tendineae, and/or the distal and/orproximal end of the band is adapted to be coupled to a second-orderchorda tendinea.

In some embodiments of the present invention, a mitral valve treatmentdevice comprises an inflatable band. The band is adapted to be placedaround between 90 and 270 degrees of a mitral valve, including around atleast a portion of a posterior cusp of the valve, in a space defined by(a) a ventricular wall, (b) a ventricular surface of the posterior cuspin a vicinity of an annulus of the mitral valve, and (c) a plurality ofthird-order chordae tendineae. After placement, the band is inflated andsealed, causing the band to press against the posterior cusp, thechordae tendineae, and the ventricular wall, thereby applying pressureto and supporting the posterior cusp. For some applications, inflationof the band additionally holds the band in place. For some applications,the band comprises neither a distal nor a proximal coupling element, orcomprises only a single coupling element.

In some embodiments of the present invention, a method for treatingmitral valve regurgitation comprises inserting a band around between 90and 270 degrees of a mitral valve, including around at least a portionof a posterior cusp of the valve, in a space defined by (a) aventricular wall, (b) a ventricular surface of the posterior cusp in avicinity of an annulus of the mitral valve, and (c) a plurality ofthird-order chordae tendineae. The method further comprises coupling adistal end and a proximal end of the band to a first chorda tendinea anda second chorda tendinea, respectively, each of the first and secondchordae tendineae selected from the group consisting of: one of theplurality of third-order chordae tendineae, and a first-order chordatendinea that inserts on a commissural cusp of the mitral valve. Suchcoupling typically tightens the annulus and thereby treats mitral valveregurgitation. Alternatively or additionally, the space is defined by aplurality of second-order chordae tendineae, and/or the distal and/orproximal end of the band is coupled to a second-order chorda tendinea.

In some embodiments of the present invention, apparatus for treating amitral valve comprises an outward force applicator adapted to be placedaround between 90 and 270 degrees of a mitral valve of a heart. Theforce applicator is configured such that at least two regions thereof(typically end regions) apply force to a wall of a heart chamber in avicinity of the commissural cusps of the mitral valve. Suchoutwardly-applied force draws the commissural cusps away from oneanother, stretching the mitral valve and thereby bringing the posteriorand anterior cusps of the valve closer to one another. The device isthus useful for treating mitral valve regurgitation.

In some embodiments of the present invention, the force applicator isadapted to be placed in a space defined by (a) a ventricular wall, (b) aventricular surface of at least one of the mitral valve cusps in avicinity of an annulus of the mitral valve, and (c) a plurality ofthird-order chordae tendineae. Alternatively or additionally, the spaceis defined by a plurality of second-order chordae tendineae. Furtheralternatively, the force applicator is adapted to be placed in a leftatrium of the heart, in contact with or in a vicinity of the mitralvalve.

In some embodiments of the present invention, the force applicatorcomprises one or more coupling elements, which are adapted to hold theforce applicator in place after placement. For some applications, thecoupling elements comprise one or more protrusions, oriented on theforce applicator such that the protrusions contact and grip the wall ofthe heart. Typically, the protrusions are positioned in a vicinity ofthe ends of the force applicator, and/or along the length of the forceapplicator, such as in a vicinity of a middle of the force applicator.For other applications, the coupling elements are adapted to be coupledto the mitral valve, and/or to one or more chordae tendineae, such asthird-order chordae tendineae, or second-order chordae tendineae. Forthese applications, the coupling elements may comprise, for example,hooks, sutures, or staples.

There is therefore provided, in accordance with an embodiment of thepresent invention, apparatus for treating mitral valve regurgitation,including:

-   -   a band having a distal and proximal ends, the band adapted to be        placed:        -   around between 90 and 270 degrees of a mitral valve,            including around at least a portion of a posterior cusp of            the valve,        -   in a space defined by (a) a ventricular wall, (b) a            ventricular surface of the posterior cusp in a vicinity of            an annulus of the mitral valve, and (c) a plurality of            third-order chordae tendineae; and    -   distal and proximal coupling elements, coupled to the band at        the distal and proximal ends thereof, respectively, and adapted        to be coupled to a first chorda tendinea and a second chorda        tendinea, respectively, each of the first and second chordae        tendineae selected from the group consisting of: one of the        plurality of third-order chordae tendineae, and a first-order        chorda tendinea that inserts on a commissural cusp of the mitral        valve.

In an embodiment, each of the first and second chordae tendineaeincludes one of the plurality of third-order chordae tendineae, and thedistal and proximal coupling elements are adapted to be coupled to therespective ones of the plurality of third-order chordae tendineae.

In an embodiment, the distal and proximal coupling elements are adaptedto be coupled to the first and second chordae tendineae such that theband tightens the annulus of the valve. Alternatively or additionally,the distal and proximal coupling elements are adapted to be coupled tothe first and second chordae tendineae such that the band appliespressure to the posterior cusp. For some applications, the distal andproximal coupling elements are adapted to be coupled to the first andsecond cusp of the valve. For some applications, the distal and proximalcoupling elements are adapted to be coupled to the first and secondchordae tendineae such that the band does not squeeze an anterior cuspof the valve and the posterior cusp together.

For some applications, the distal and proximal coupling elements includerespective hooks, adapted to be hooked to the first and second chordaetendineae, respectively.

For some applications, the band is generally elliptical incross-section. Alternatively, the band is flat.

For some applications, the band includes at least one sensor selectedfrom the group consisting of: a wireless position sensor, and anavigation sensor. For some applications, the band includes a steeringmechanism.

For some applications, the band includes a shape memory alloy, and theshape memory alloy causes the band to assume a curved shape duringplacement of the band.

For some applications, the band includes a tension element, adapted toshorten a length of the band. For some applications, at least a portionof the band includes an elastic material, adapted to shorten a length ofthe band.

For some applications, the band is coated with a substance selected fromthe group consisting of: a drug, and a radiopaque coating.

For some applications, the band is adapted to be placed around noportion of an anterior cusp of the valve. For some applications, theband is adapted to be placed such that a length of a first portion ofthe band that surrounds the at least a portion of the posterior cusp isat least 5 times a total length of that portion of the band thatsurrounds at least a portion of an anterior cusp of the valve.

For some applications, the band includes a distal stop, and the distalcoupling element is adapted to slide along the band until blocked by thedistal stop.

For some applications, the band includes a plurality of bands, the bandsadapted to be placed in series around between 90 and 270 degrees of themitral valve.

For some applications, the apparatus includes an elongated insertionelement, adapted to releasable engage the proximal end of the band.

In an embodiment, the proximal coupling element is adapted to slidealong the band and subsequently be locked to the band. For someapplications, a portion of the band in a vicinity of the proximal end isshaped so as to define a first set of teeth, an interior surface of theproximal coupling element is shaped to as to define a second set ofteeth, and the teeth are configured to allow distal advancement of theproximal coupling element along the band, and to not allow proximalretraction of the proximal coupling element along the band.

For some applications, the apparatus includes a crimping mechanism,adapted to be placed around the proximal coupling element and to crimpthe proximal coupling element to the band.

For some applications, a portion of the band in a vicinity of theproximal end is shaped so as to define a first set of teeth, an interiorsurface of the proximal coupling element is shaped so as to define asecond set of teeth, and the crimping element is adapted to crimp theproximal coupling element to the band by crimping at least a portion ofthe second set of teeth to at least a portion of the first set of teeth.For some applications, the crimping mechanism includes an inflationelement, adapted, upon inflation thereof, to crimp the proximal couplingelement to the band.

For some applications, the band is shaped so as to define one or moreindentations therein, and the proximal coupling element includes atension clip, adapted to engage at least one of the indentations, so asto lock the proximal coupling element to the band.

For some applications, the band is adapted to be placed around between120 and 240 degrees of the mitral valve, such as between 150 and 210degrees of the mitral valve.

There is also provided, in accordance with an embodiment of the presentinvention, apparatus for treating mitral valve regurgitation, including:

-   -   a band having distal and proximal ends, the band adapted to be        placed:        -   around between 90 and 270 degrees of a mitral valve,            including around at least a portion of a posterior cusp of            the valve,        -   in a space defined by (a) a ventricular wall, (b) a            ventricular surface of the posterior cusp in a vicinity of            an annulus of the mitral valve, and (c) a plurality of            second-order chordae tendineae; and    -   distal and proximal coupling elements, coupled to the band at        the distal and proximal ends thereof, respectively, and adapted        to be coupled to a first chorda tendinea and a second chorda        tendinea, respectively, each of the first and second chordae        tendineae selected from the group consisting of: one of the        plurality of second-order chordae tendineae, and a first-order        chorda tendinea that inserts on a commissural cusp of the mitral        valve.

There is further provided, in accordance with an embodiment of thepresent invention, apparatus for treating mitral valve regurgitation,including a band adapted to be placed:

-   -   around between 90 and 270 degrees of a mitral valve of a heart,        including around at least a portion of a posterior cusp of the        valve,    -   in a space defined by (a) a ventricular wall, (b) a ventricular        surface of the posterior cusp in a vicinity of an annulus of the        mitral valve, and (c) a plurality of third-order chordae        tendineae,    -   the band configured such that inflation thereof applies pressure        to the posterior cusp.

In an embodiment, the band is configured such that inflation thereofholds the band in place.

For some applications, the apparatus includes a liquid for inflating theband, the liquid adapted to at least partially solidify after inflationof the band therewith.

In an embodiment, the band is not configured to be coupled to anyportion of the heart, other than by the inflation thereof.

There is still further provided, in accordance with an embodiment of thepresent invention, apparatus for treating mitral valve regurgitation,including a band adapted to be placed:

-   -   around between 90 and 270 degrees of a mitral valve, including        around at least a portion of a posterior cusp of the valve,    -   in a space defined by (a) a ventricular wall, (b) a ventricular        surface of the posterior cusp in a vicinity of an annulus of the        mitral valve, and (c) a plurality of second-order chordae        tendineae,    -   the band configured such that inflation thereof applies pressure        to the posterior cusp.

In an embodiment, the band is configured such that inflation thereofholds the band in place.

There is yet further provided, in accordance with an embodiment of thepresent invention, apparatus for treating mitral valve regurgitation,including:

-   -   a stent, adapted to be placed while in a contracted state around        between 90 and 270 degrees of a mitral valve of a heart,        including around at least a portion of a posterior cusp of the        valve, in a space defined by (a) a ventricular wall, (b) a        ventricular surface of the posterior cusp in a vicinity of an        annulus of the valve, and (c) a plurality of third-order chordae        tendineae; and    -   an inflation element, positioned within the stent, and adapted        to expand the stent upon inflation, such that the stent applies        pressure to the posterior cusp.

In an embodiment, the stent includes at least one coupling element,adapted to be coupled to a chorda tendinea.

For some applications, the stent includes a plurality of stents, adaptedto be placed in series around between 90 and 270 degrees of the mitralvalve.

There is additionally provided, in accordance with an embodiment of thepresent invention, a method for treating mitral valve regurgitation,including:

-   -   inserting a band around between 90 and 270 degrees of a mitral        valve, including around at least a portion of a posterior cusp        of the valve, in a space defined by (a) a ventricular wall, (b)a        ventricular surface of the posterior cusp in a vicinity of an        annulus of the valve, and (c) a plurality of third-order chordae        tendineae; and    -   coupling a distal end and a proximal end of the band to a first        chorda tendinea and a second chorda tendinea, respectively, each        of the first and second chordae tendineae selected from the        group consisting of: one of the plurality of third-order chordae        tendineae, and a first-order chorda tendinea that inserts on a        commissural cusp of the mitral valve.

For some applications, inserting includes inserting the band via anascending aorta.

For some applications, the band includes at least one sensor selectedfrom the group consisting of: a wireless position sensor, and anavigation sensor, and inserting includes inserting the band at least inpart responsively to a signal generated by the sensor.

For some applications, the band includes a distal stop and a distalcoupling element, and coupling the distal end of the band to the firstchorda tendinea includes:

-   -   advancing the band until the distal stop reaches a vicinity of a        first chorda tendinea;    -   advancing the distal coupling element over the band until the        distal coupling element reaches the distal stop; and    -   coupling the distal coupling element to the first chorda        tendinea.

In an embodiment, the band includes a proximal coupling element, andcoupling includes:

-   -   coupling the distal end of the band to the first chorda        tendinea;    -   thereafter, sliding the proximal coupling element along the band        until the band has a desired length between the distal end and        the proximal coupling element; and    -   locking the proximal coupling element to the band.

For some applications, coupling includes, after locking the proximalcoupling element, clipping a portion of the band proximal to theproximal coupling element. For some applications, coupling includes,after locking the proximal coupling element, releasing the band from anelongated insertion element, and withdrawing the insertion element fromthe heart.

For some applications, a portion of the band in a vicinity of theproximal end includes a first set of teeth, an interior surface of theproximal coupling element includes a second set of teeth, the teeth areconfigured to allow distal advancement of the proximal coupling elementalong the band, and to not allow proximal retraction of the proximalcoupling element along the band, and locking the proximal couplingelement includes advancing the proximal coupling element until the bandhas the desired length.

There is yet additionally provided, in accordance with an embodiment ofthe present invention, a method for treating mitral valve regurgitation,including:

-   -   inserting a band around between 90 and 270 degrees of a mitral        valve, including around at least a portion of a posterior cusp        of the valve, in a space defined by (a) a ventricular wall, (b)        a ventricular surface of the posterior cusp in a vicinity of an        annulus of the valve, and (c) a plurality of second-order        chordae tendineae; and    -   coupling a distal end and a proximal end of the band to a first        chorda tendinea and a second chorda tendinea, respectively, each        of the first and second chordae tendineae selected from the        group consisting of: one of the plurality of second-order        chordae tendineae, and a first-order chorda tendinea that        inserts on a commissural cusp of the mitral valve.

There is still additionally provided, in accordance with an embodimentof the present invention, a method for treating mitral valveregurgitation, including:

-   -   inserting a band around between 90 and 270 degrees of a mitral        valve of a heart, including around at least a portion of a        posterior cusp of the valve, in a space defined by (a) a        ventricular wall, (b) a ventricular surface of the posterior        cusp in a vicinity of an annulus of the valve, and (c) a        plurality of third-order chordae tendineae; and    -   applying pressure to the posterior cusp by inflating the band.

There is also provided, in accordance with an embodiment of the presentinvention, a method for treating mitral valve regurgitation, including:

-   -   inserting a band around between 90 and 270 degrees of a mitral        valve, including around at least a portion of a posterior cusp        of the valve, in a space defined by (a) a ventricular wall, (b)        a ventricular surface of the posterior cusp in a vicinity of an        annulus of the valve, and (c) a plurality of second-order        chordae tendineae; and    -   applying pressure to the posterior cusp by inflating the band.

There is further provided, in accordance with an embodiment of thepresent invention, a method for treating mitral valve regurgitation,including:

-   -   inserting a stent in a contracted state around between 90 and        270 degrees of a mitral valve of a heart, including around at        least a portion of a posterior cusp of the valve, in a space        defined by (a) a ventricular wall, (b) a ventricular surface of        the posterior cusp in a vicinity of an annulus of the valve,        and (c) a plurality of third-order chordae tendineae; and    -   applying pressure to the posterior cusp by expanding the stent        by inflating an inflation element positioned within the stent.

There is still further provided, in accordance with an embodiment of thepresent invention, apparatus for treating mitral valve regurgitation,including a force applicator adapted to be placed around at least aportion of a mitral valve of a heart, and configured such that at leasttwo regions of the force applicator apply, to a wall of a chamber of theheart in a vicinity of commissural cusps of the mitral valve, forcesufficient to bring a posterior cusp and an anterior cusp of the mitralvalve closer to one another than a distance therebetween in the absenceof the force applicator.

In an embodiment, the applicator is adapted to be placed in a spacedefined by (a) a ventricular wall, (b) a ventricular surface of thepositioning cusp in a vicinity of an annulus of the valve, and (c) aplurality of third-order chordae tendineae. Alternatively, in anembodiment, the applicator is adapted to be placed in a space defined by(a) a ventricular wall, (b) a ventricular surface of the posterior cuspin a vicinity of an annulus of the valve, and (c) a plurality ofsecond-order chordae tendineae.

In an embodiment, the applicator is adapted to be placed in a leftatrium of the heart, in contact with or in a variety of the mitralvalve.

For some applications, the applicator is generally elliptical incross-section. Alternatively, the applicator is flat.

For some applications, the applicator is coated with a substanceselected from the group consisting of: a drug, and a radiopaque coating.

For some applications, the applicator is adapted to be placed around noportion of the anterior cusp. For some applications, the applicator isadapted to be placed such that a length of a first portion of theapplicator that surrounds at least a portion of the posterior cusp is atleast 5 times a total length of that portion of the applicator thatsurrounds at least a portion of the anterior cusp.

For some applications, the applicator is configured to enhance fibrosisbetween at least a portion of the applicator and the wall of thechamber.

For some applications, the applicator includes at least one sensorselected from the group consisting of: a wireless position sensor, and anavigation sensor. For some application, the applicator includes asteering mechanism.

For some applications, the applicator has distal and proximal ends, andthe applicator includes an adjustment mechanism, which is configured tochange a distance between the distal end and the proximal end of theapplicator.

For some applications, the applicator is shaped so as to define one ormore protrusions, oriented such that the protrusions contact the wall ofthe chamber of the heart upon placement of the applicator.

In an embodiment, the applicator includes one or more coupling elements,adapted to hold the applicator in place around the at least a portion ofthe valve. Alternatively, the coupling elements are adapted to becoupled to respective chordae tendineae.

In an embodiment, the applicator is adapted to be placed around between90 and 270 degrees of the mitral valve, such as around between 120 and240 degrees of the initial valve, e.g., around between 150 and 210degrees of the mitral valve.

In an embodiment, the applicator is configured such that after placementof the applicator, and before the at least two regions apply the force,there is a gap between the applicator and the wall of the chamber. Forsome applications, the applicator is configured such that the forceapplied by the at least two regions reduces a distance between theapplicator and the wall of the chamber in a vicinity of the gap. Forsome applications, the applicator is configured such that the forceapplied by the at least two regions immediately reduces the distance.Alternatively, the applicator is configured such that the force appliedby the at least two regions reduces the distance within one month ofapplication of the force.

In an embodiment, the at least two regions include two end regions ofthe force applicator, and the force applicator is configured such thatat least the two end regions apply the force. For some applications, theapplicator includes at least one screw in a vicinity of at least one ofthe end regions, the screw configured such that rotation thereof adjusta degree of pushing of the at least one end region into the wall of thechamber.

There is additionally provided, in accordance with an embodiment of thepresent invention, apparatus for treating mitral valve regurgitation,including a force applicator adapted to be place around at least aportion of a mitral valve of a heart, and configured to:

-   -   apply force to a wall of a chamber of the heart, so as to change        a shape of the heart around the mitral valve, and    -   enhance fibrosis between at least a portion of the force        applicator and the heart wall, so as to help maintain the        changed shape of the heart.

For some applications, a surface of the at least a portion of theapplicator is roughened to enhance fibrosis. Alternatively oradditionally, the at least a portion of the applicator is coated with afibrosis-enhancing substance.

There is yet additionally provided, in accordance with an embodiment ofthe present invention, a method for treating mitral valve regurgitation,including placing, around at least a portion of a mitral valve of aheart, a force applicator configured such that at least two regions ofthe force applicator apply, to a wall of a chamber of the heart in avicinity of commissural cusps of the mitral valve, force sufficient tobring a posterior cusp and an anterior cusp of the mitral valve closerto one another than a distance therebetween in the absence of the forceapplicator.

For some applications, the applicator includes at least one sensorselected from the group consisting of: a wireless position sensor, and anavigation sensor, and placing include placing the applicator at leastin part responsively to a signal generated by the sensor.

There is also provided, in accordance with an embodiment of the presentinvention, a method for treating mitral valve regurgitation, includingplacing, around at least a portion of a mitral valve of a heart, a forceapplicator configured to apply force to a wall of a chamber of theheart, so as to change a shape of the heart around the mitral valve, andto enhance fibrosis between at least a portion of the force applicatorand the heart well, so as to help maintain the changed shape of theheart.

The present invention will be more fully understood from the followingdetailed description of embodiments thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a mitral valve treatment device,in accordance with an embodiment of the present invention;

FIG. 2 is a schematic illustration of the device of FIG. 1 placed in aheart, in accordance with an embodiment of the present invention;

FIG. 3 is a schematic illustration of a pardon of the device of FIG. 1placed around a portion of a posterior cusp of a mitral valve, inaccordance with an embodiment of the present invention; and

FIG. 4 is a schematic illustration of a procedure for introducing thedevice of FIG. 1 into the heart, in accordance with an embodiment of thepresent invention;

FIG. 5 is a schematic illustration of a distal end of a catheter forintroducing the device of FIG. 1 into the heart, in accordance with anembodiment of the present invention;

FIGS. 6A-B are schematic illustrations of a mitral valve before andafter placement of the device of FIG. 1, respectively, in accordancewith an embodiment of the present invention;

FIGS. 7A-B are schematic illustrations of the device of FIG. 1 duringsystole and diastole, respectively, in accordance with an embodiment ofthe present invention;

FIGS. 8A-B are schematic illustration of an over-the-wire implementationof the device of FIG. 1, in accordance with an embodiment of the presentinvention;

FIGS. 9A-B are schematic illustrations of a sliding and lookingmechanism of the device of FIG. 1, in accordance with an embodiment ofthe present invention;

FIGS. 10A-C are schematic illustrations of another sliding and lockingmechanism of the device of FIG. 1, in accordance with an embodiment ofthe present invention;

FIGS. 11A-B are schematic illustrations of yet another sliding andlocking mechanism of the device of FIG. 1, in accordance with anembodiment of the present invention;

FIGS. 12A-B are schematic illustrations of a band clipping mechanism, inaccordance with an embodiment of the present invention;

FIGS. 13A-B are schematic illustrations of a band release mechanism, inaccordance with an embodiment of the present invention;

FIGS. 14A-B are schematic illustrations of an influence mechanism, inaccordance with an embodiment of the present invention;

FIGS. 15A-B are schematic illustrations of another inflation technique,in accordance with an embodiment of the present invention;

FIG. 16 is a schematic illustration of a configuration of the device ofFIG. 1, in accordance with an embodiment of the present invention;

FIGS. 17A-B are schematic illustrations of a stent adapted for treatmentof a mitral valve, in accordance with an embodiment of the presentinvention.

FIG. 18 is a schematic illustration of a mitral valve treatment forceapplicator placed in a heart, in accordance with an embodiment of thepresent invention;

FIGS. 19A and 19B are schematic illustrations of a mitral valve beforeand after placement of the force applicator of FIG. 18, respectively, inaccordance with an embodiment of the present invention;

FIG. 20 is a schematic illustration of a portion of the force applicatorof FIG. 18 placed around a portion of a posterior cusp of the mitralvalve, in accordance with an embodiment of the present invention;

FIGS. 21A and 21B are schematic illustrations of the mitral valve beforeand after expansion of the force applicator of FIG. 18, respectively, inaccordance with an embodiment of the present invention;

FIGS. 22 and 23 are schematic illustrations of respective configurationsof the force applicator of FIG. 18, in accordance with respectiveembodiments of the present invention;

FIG. 24 is a schematic illustration of a procedure for introducing theforce applicator of FIG. 18 into the heart of a subject, in accordancewith an embodiment of the present invention;

FIG. 25 is a schematic illustration of a distal end of a catheter forintroducing the force applicator of FIG. 18 into the heart, inaccordance with an embodiment of the present invention; and

FIGS. 26 and 27 are schematic illustrations of respective adjustmentmechanisms for the force applicator of FIG. 18, in accordance withrespective embodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic illustration of a mitral valve treatment device20, in accordance with an embodiment of the present invention. Device 20typically comprise a flexible band 30, a distal coupling element 32(e.g., a hook), and a proximal coupling element 34 (e.g., a hook). Forsome applications, band 30 is generally elliptical in cross-section(e.g., circular), while for other applications the band is flat, e.g.,ribbon-shaped. Band 30 typically comprises a biocompatible material,such as a polymer or metal. For some applications, band 30 is coatedwith a drug and/or a radiopaque coating.

Reference is made to FIG. 2, which is a schematic illustration of band30 placed in a heart 50, which is viewed from above the heart with theatria removed, in accordance with an embodiment of the presentinvention. Band 30 is adapted to be placed around between 90 and 270degrees of a mitral valve 58 of a heart 50, including around at least aportion of a posterior cusp 56 of mitral valve 58, in a vicinity of anannulus 60 of mitral valve 58. For some applications, band 30 is adaptedto be placed around between 120 and 240 degrees, such as between 150 and210 degrees, e.g., about 180 degrees, of the mitral valve. For someapplications, band 30 is adapted to be placed substantially only aroundall or a portion of posterior cusp 56, i.e., substantially not aroundany portion of an anterior cusp 59 of mitral valve 58. For example, thelength of band 30 surrounding posterior cusp 56 is typically at leastabout 5 or at least about 10 times the length of any portion of band 30that may be surrounding anterior cusp 59.

For some applications, band 30 is anchored in place by distal couplingelement 32 and proximal coupling element 34, such that the band appliespressure to posterior cusp 56, thereby tightening annulus 60, supportingthe posterior cusp, and bringing the posterior cusp closer to theanterior cusp. For applications in which a portion of band 30 is placedaround a portion of anterior cusp 59, band 30 typically applies forcesubstantially only to posterior cusp 56. Furthermore, band 30 istypically configured to apply pressure to posterior cusp 56, rather thanto squeeze the posterior and anterior cusps together.

Reference is made to FIG. 3, which is a schematic illustration of aportion of band 30 placed around a portion of posterior cusp 56, inaccordance with an embodiment of the present invention. Typically, band30 is placed in the space defined by a ventricular wall 70 of leftventricle 72, a ventricular surface of posterior cusp 56 in a vicinityof annulus 60, and third-order chordae tendineae 74 (also calledtertiary or basal chordae). (Third-order chordae 74, of which only twoof many are shown in the figure for clarity of illustration, originatedirectly from the trabeculae carneae of ventricular wall 70, and attachto posterior cusp 56 in a vicinity of annulus 60.) Alternatively oradditionally, the space is defined by second-order chordae tendineae(not shown in the figure). Typically, distal and proximal couplingelements 32 and 34 are coupled to first and second chordae tendineae,respectively, each of which is selected from the group consisting of:one of third-order chordae 74, a first-order chorda tendinea thatinserts on a commissural cusp 78 of mitral valve 58 (shown in FIG. 2),and a second-order chorda tendinea (not shown in the figures).Typically, when in place, band 30 is in contact with one or more third-or second-order chordae tendineae, and/or the ventricular surface ofposterior cusp 56 in the vicinity of annulus 60.

Alternatively or additionally, band 30 is placed around first-orderchordae tendineae 80 that inserts on posterior cusp 56, anterior cusp59, and/or commissural cusps 78 (configuration not shown in thefigures). Further alternatively or additionally, band 30 is wovenbetween the first-, second-, and/or third-order chordae.

Reference is made to FIG. 4, which is a schematic illustration of aprocedure for introducing device 20 into heart 50 of a subject, inaccordance with an embodiment of the present invention. Typically,device 20 is introduced into ventricle 72 by a catheter 81, which istypically introduced into ventricle 72 via an ascending aorta 82. Asurgeon typically guides device 20 to a desired location using images ofheart 50 captured using techniques known in the art. For someapplications, device 20 comprises, e.g., at a distal and thereof, one ormore wireless position sensors, such as those manufactured by Biosense,Inc. (New Brunswick, N.J.), or otherwise known in the art. Alternativelyor additionally, device 20 comprises, e.g., at a distal end thereof, oneor more sensors for aiding navigation, such as an ultrasound sensor, aninfrared sensor, or an optical sensor. For some applications, device 20comprises a steering mechanism, such as those known in the art ofcoronary catheter navigation. For some applications, band 30 comprises ashape memory alloy, such as nitinol, which causes the band to assume acurved shape, thereby assisting in navigating the band around thechordae tendineae. For some applications, the surgeon magneticallynavigates band 30, such as using techniques described in U.S. Pat. Nos.6,817,364 or 6,522,909 to Garibaldi et al., or U.S. Pat. No. 6,475,223to Werp et al., which are incorporated herein by reference, mutatismutandis.

Reference is made to FIG. 5, which is a schematic illustration of adistal end 84 of catheter 81, in accordance with an embodiment of thepresent invention. In this embodiment, the distal end of catheter 81opens laterally, rather than at its end, so as to guide device 20towards mitral valve 58 after the catheter is inserted into leftventricle 72.

Reference is made to FIGS. 6A-B, which are schematic illustrations ofmitral valve 58 before and after placement of band 30, respectively, inaccordance with an embodiment of the present invention. FIG. 6A showsmitral valve regurgitation occurring prior to the placement of band 30.FIG. 6A also shows band 30 as it is being placed around posterior cusp56. FIG. 6B shows band 30 after it has been anchored in place aroundposterior cusp 56, thereby preventing regurgitation.

Reference is again made to FIG. 1. In an embodiment of the presentinvention, band 30 is adapted to tense, so as to shorten its length. Forsome applications, band 30 comprises a tension element 88, such as aspring. Alternatively or additionally, all or a portion of band 30comprises an elastic material. For some applications, the tension servesto increase the force applied by band 30 to posterior cusp 56 after theband has been coupled to the chordae tendineae.

Reference is now made to FIGS. 7A-B, which are schematic illustrationsof band 30 during systole and diastole, respectively, in accordance withan embodiment of the present invention. In this embodiment, band 30comprises tension element 88, and/or band 30 comprises an elasticmaterial. As shown in FIG. 7A, during systole tension element 88contracts, increasing the pressure applied by band 30 to posterior cusp56. During diastole, as shown in FIG. 7B, tension element 88 expands,reducing the pressure applied by band 30 to posterior cusp 56, andallowing mitral valve 58 to open.

Reference is now made to FIGS. 8A-B, which are schematic illustrationsof an over-the-wire implementation of device 20, in accordance with anembodiment of the present invention. In this embodiment, band 30comprises a distal stop 100, which, for example, may be spherical.Distal coupling element 32 is adapted to slide distally along band 30until blocked by distal stop 100. During placement, band 30 is advanceduntil distal stop 100 reaches a vicinity of the chorda tendinea to whichthe distal end of the band will be coupled. Distal coupling element 32is then advanced over band 30 until it reaches the distal end of theband. For example, the surgeon may advance catheter 81 over band 30 inorder to push distal coupling element 32 to the distal end of the band.The surgeon then couples the coupling element to the chorda tendinea.Typically, the coupling of distal coupling element 32 to the chordatendinea prevents subsequent proximal sliding of the coupling element.Alternatively, a locking mechanism is provided to hold coupling element32 in place once it reaches distal stop 100. The use of distal stop 100and the techniques described in this paragraph typically enable easieradvancement of band 30 than in embodiments in which distal couplingelement 32 is fixed to the distal end of band 30 during advancement.

Reference is again made to FIG. 1. In an embodiment of the presentinvention, proximal coupling element 34 comprises a sliding and lockingmechanism 90. Sliding and locking mechanism 90 is configured to have alocked position and an unlocked position. When in the unlocked position,the mechanism is able to slide along band 30, and when in the lockedposition, the mechanism is fixed to the band. Typically, duringplacement of device 20 a surgeon couples distal coupling element 32 to achorda tendinea at a desired location, and slides proximal couplingelement 34 along band 30 so that band 30 has a desired length betweenthe two coupling elements. The surgeon then locks mechanism 90, andclips the portion of band 30 proximal to proximal coupling element 34.For some applications, the surgeon locks and/or clips the excess portionbefore coupling proximal coupling element to a chorda tendinea, whilefor other applications the surgeon locks and/or clips the excess portionafter coupling proximal coupling element to a chorda tendinea.Alternatively, rather than being clipped, band 30 is released from arelease mechanism, as described hereinbelow with reference to FIGS.13A-B.

Typically, the tension of band 30 is determined by the selected lengthof band 30 and the locations at which coupling elements 32 and 34 arecoupled to the chordae. For some applications, the surgeon adjusts thetension of band 30 based on (a) tactile feedback, (b) a forcemeasurement, and/or (c) another measurement, such as anelectrocardiographic measurement, and/or a blood flow measurement madein the heart or elsewhere in the body. For some applications, band 30comprises at least one tension or pressure sensor 86, which is adaptedto measure the tension of band 30. Alternatively or additionally, device20 comprises a tension control system 87 proximal to proximal couplingelement 34.

Reference is made to FIGS. 9A-B, which are schematic illustrations ofanother sliding and locking mechanism 120 of band 30, in accordance withan embodiment of the present invention. Mechanism 120 comprises twointerlocking sets of teeth. A first set of teeth 130 is coupled to orintegrated into a proximal portion of band 30, and a second set of teeth132 is coupled to or integrated into an interior surface of proximalcoupling element 34. The teeth are configured to allow distaladvancement of coupling element 34 over band 30, but to not allowproximal retraction of the coupling element. The surgeon distallyadvances coupling element 34 over band 30 so that band 30 has a desiredlength between the two coupling elements.

Reference is made to FIGS. 10A-C, which are schematic illustrations ofyet another sliding and locking mechanism 140 of band 30, in accordancewith an embodiment of the present invention. Mechanism 140 comprises twointerlocking sets of teeth. A first set of teeth 150 is coupled to orintegrated into a proximal portion of band 30, and a second set of teeth152 is coupled to or integrated into an interior surface of proximalcoupling element 34. When the coupling element is in an unlockedposition, the first and second sets of teeth are not engaged with oneanother, such that the coupling element is able to advance distally overband 30, as shown in FIG. 10A. Catheter 81 comprises a crimpingmechanism 153 in a vicinity of a distal end of the catheter. Crimpingmechanism 153 typically comprises an expansion element 154, such as aballoon, which is coupled to an external source 156 of fluid (liquid orgas) pressure, via a pressure tube 158. Crimping mechanism 153 isadapted to be placed around the portion of proximal coupling element 34having second set of teeth 152, as shown in FIG. 10A. Crimping mechanism153 is configured such that expansion of expansion element 154 pushessecond set of teeth 152 into contact with first set of teeth 150,crimping the first and second sets of teeth together, as shown in FIG.10B. Such crimping locks coupling element 34 in place on band 30. Aftercrimping, catheter 81 and crimping mechanism 153 are retracted, leavingcoupling element 34 in place, as shown in FIG. 10C.

Reference is made to FIGS. 11A-B, which are schematic illustrations ofstill another sliding and locking mechanism 170, in accordance with anembodiment of the present invention. Mechanism 170 comprises a tensionclip 172 that releasably engages one or more indentations 174 in band30. Tension clip 172 is configured such that in its resting position,coupling portions 176 of the clip engage respective indentations 174,preventing movement of the clip, as shown in FIG. 11A. Applying force torelease sites 178 of clip 172 changes the shape of the clip, causingcoupling portions 176 to disengage from indentations 174, as shown inFIG. 11B. For some applications, release sites 178 also serve ascoupling elements for coupling band 30 to the chordae tendineae, whilefor other applications, clip 172 comprises separate coupling elements(latter configuration not shown). In an embodiment, catheter 81comprises one or more force application elements 180, which areconfigured to apply force to release sites 178, in order to disengageclip 172 from band 30. For some applications, force application elements180 are inflatable, and are configured such that inflation thereofapplies force to release sites 178.

Reference is made to FIGS. 12A-B, which are schematic illustrations of aband clipping mechanism 200, in accordance with an embodiment of thepresent invention. Clipping mechanism 200 is used to clip the portion ofband 30 proximal to proximal coupling element 34, typically after theproximal coupling element has been locked in place. Clipping mechanism200 comprises clippers 210, which are adapted to be introduced throughcatheter 81 over the proximal portion of band 30. Clippers 210 clip theband, and the clippers and the proximal portion of the band arewithdrawn through catheter 81, leaving the distal portion of band 30 inplace in the heart, as shown in FIG. 12B.

Reference is made to FIGS. 13A-B, which are schematic illustrations of aband release mechanism 220, in accordance with an embodiment of thepresent invention. The release mechanism is used to release band 30 froman insertion element 224, which is subsequently withdrawn throughcatheter 81. Therefore, in this embodiment, there is generally no needto clip the band. Release mechanism comprises a grasping element 226,which is adapted to releasably engage the proximal end of band 30. Forsome applications, the proximal end of band 30 comprises or is shaped toas to define a protrusion 228, such as a spherical protrusion, whichgrasping element 226 engages. Alternatively, release mechanism 220comprises another coupling element such as a screw, which releasablyengages the proximal end of band 30.

In an embodiment of the present invention, proximal coupling element 34does not comprise sliding and locking mechanism 90 or any otherlength-adjusting mechanism, such that the length of band 30 is fixed. Inthis embodiment, the surgeon may or may not invasively or non-invasivelymeasure or estimate the circumference of annulus 60 prior to choosingwhich length of band 30 to implant. For some applications of thisembodiment, band 30 comprises band release mechanism 220, describedhereinabove with reference to FIGS. 13A-B.

In an embodiment of the present invention, band 30 is configured suchthat distal and proximal coupling elements 32 and 34 push the chordaetendineae to which they are coupled, rather than pull the chordae. Inthis embodiment, band 30 is typically stiffer than in some otherembodiments described herein.

In an embodiment of the present invention, band 30 comprises one or moresupporting members configured to support posterior cusp 56. For someapplications, the supporting members protrude from the band.

Reference is made to FIGS. 14A-B, which are schematic illustrations ofan inflation mechanism 300, in accordance with an embodiment of thepresent invention. Inflation mechanism 300 comprises an inflatablesheath 310, placed around band 30, and an external source 312 of liquid(fluid or gas) pressure, which is coupled to an interior of sheath 310via a pressure tube 314. During insertion of band 30, sheath 310 istypically uninflated. After insertion, pressure source 312 inflatessheath 310 by supplying a liquid or gas, such as saline solution, aliquid silicone, a liquid polymer, or a liquid polyurethane. Afterinflation, sheath 310 is sealed. Such inflation typically increases thesupport band 30 provides to posterior cusp 56. For some applications,sheath 310 is inflated with a liquid that completely or partiallysolidifies after inflation, such as into a flexible material.

FIGS. 15A-B are schematic illustrations of another inflation technique,in accordance with an embodiment of the present invention. In thisembodiment, band 30 is itself inflatable, and sheath 310 need not beprovided. The interior of band 30 is in fluid communication withexternal pressure source 312 via pressure tube 314. This embodiment mayemploy techniques described hereinabove with references to FIGS. 14A-B,mutatis mutandis.

FIG. 16 is a schematic illustration of a configuration of band 30, inaccordance with an embodiment of the present invention. In thisembodiment, band 30 is inflatable, such as by using one of the inflationtechniques described hereinabove with reference to FIGS. 14A-B or 15A-B.For some applications, inflation band 30 comprises neither distalcoupling element 32 nor proximal coupling element 34, nor any otheranchoring means at either the distal or proximal ends of the band.(Alternatively, for some applications, band 30 comprises anchoring meansat only a single one of its ends.) After the band is placed around allor a portion of posterior cusp 56, the band is inflated and sealed,causing the band to press against posterior cusp 56, chordae tendineae74 (or, alternatively, the second-order chordae tendineae), andventricular wall 70, thereby applying pressure to and supporting theposterior cusp, and typically holding band 30 in place.

Reference is made to FIGS. 17A-B, which are schematic illustrations of astent 350 adapted for treatment of mitral valve 58, in accordance withan embodiment of the present invention. Stent 350 is adapted to beplaced around between 90 and 270 degrees of mitral valve 58, includingaround at least a portion of posterior cusp 56. For some applications,stent 350 is adapted to be placed around between 120 and 240 degrees,such as between 150 and 210 degrees, e.g., about 180 degrees, of themitral valve. For some applications, stent 350 is adapted to be placedsubstantially only around all or a portion of posterior cusp 56, i.e.,substantially not around any portion of anterior cusp 59. For example,the length of stent 350 surrounding posterior cusp 56 is typically atleast about 5 or at least about 10 times the length of any portion ofstent 350 that may be surrounding anterior cusps 59.

Typically, stent 350, while in a contracted position, as shown in FIG.17A, is placed in the space defined by ventricular wall 70 of leftventricle 72, a ventricular surface of posterior cusp 56 in a vicinityof annulus 60, and chordae tendineae selected from third-order chordaetendineae 74 and second-order chordae tendineae. Once in its desiredposition, stent 350 is expanded by inflating an inflation element 360positioned within the stent. Inflation element 360 is removed, leavingstent 350 in place. Expansion of stent 350 applies pressure to andsupports posterior cusp 56, and typically holds the stent in place.

For some applications, one or both ends of stent 350 are anchored inplace by distal and/or proximal coupling elements (not shown in FIGS.17A-B, but similar to distal and proximal coupling elements 32 and 34,as described hereinabove). Typically, the distal and proximal couplingelements are coupled to first and second chordae tendineae,respectively, each of which is selected from the group consisting of:one of third-order chordae 74, a first-order chorda tendinea thatinserts on a commissural cusp 78 of mitral valve 58 (shown in FIG. 2),and a second-order chorda tendinea (not shown in the figures).

For some applications, a plurality of stents 350 are placed aroundmitral valve 58. The plurality of stents are typically arranged inseries, and are optionally coupled to one another.

In an embodiment of the present invention, a method is provided forremoving band 30 after it has been coupled to the chordae tendineae. Themethod comprises inserting a catheter or other elongated element intothe heart, typically via ascending aorta 82, and navigating the catheteraround the chordae tendineae in a direction opposite to the direction inwhich band 30 was navigated around the chordae during insertion of theband. When the catheter reaches the distal end of band 30, the catheteris coupled to the distal end. The catheter is then withdrawn, such thatband 30 is pulled in the same direction as during the band's initialinsertion. For example, if band 30 is initially inserted in acounterclockwise direction around the mitral valve as viewed from theleft atrium, the catheter is inserted in a clockwise direction, and thecatheter is withdrawn, pulling band 30, in a counterclockwise direction.Typically, before removing band 30, proximal coupling element 34 isremoved from the band. For some applications, distal stop 100 ismagnetic, and the catheter is magnetically coupled to the distal stop.

It will be appreciated that whereas band 30 has been generally describedherein as comprising a single band, the scope of the present inventionis not limited to a single band, and includes the use of multiple bandsin series and/or in parallel with one another.

FIG. 18 is a schematic illustration of a mitral valve treatment outwardforce applicator 430 placed in heart 50, which is viewed from above theheart with the atria removed, in accordance with an embodiment of thepresent invention. Force applicator 430 is typically flexible, and, forsome applications, is generally elliptical in cross-section (e.g.,circular), while for other applications is flat, e.g., ribbon-shaped.Force applicator 430 typically comprises a biocompatible material, suchas a polymer or metal. For some applications, force applicator 430 iscoated with a drug and/or a radiopaque coating.

Force applicator 430 is adapted to be placed around between 90 and 270degrees of mitral valve 58 of heart 50, in a vicinity of annulus 60 ofmitral valve 58. The ends of force applicator 430 are typically, but notnecessarily, positioned in a vicinity of commissural cusps 78 of mitralvalve 58. Force applicator 430 is configured such that at least tworegions thereof (typically end regions 462) apply force, symbolicallyindicated by arrows 464, to a wall 466 of a heart chamber in a vicinityof commissural cusps 78. The heart chamber is the left ventricle and/orthe left atrium. Such outwardly-applied force draws commissural cusps 78away from one another, stretching mitral valve 58 and thereby bringingposterior cusp 56 and anterior cusp 59 of mitral valve 58 closer to oneanother.

For some applications, force applicator 430 is adapted to be placedaround between 120 and 240 degrees, such as between 150 and 210 degrees,e.g., about 180 degrees, of mitral valve 58. For some applications,force applicator 430 is adapted to be placed substantially only aroundall or a portion of posterior cusp 56, i.e., substantially not aroundany portion of anterior cusp 59. For example, for these applications,the length of force applicator 430 surrounding posterior cusp 56 may beat least about 5 or at least about 10 times the length of any portion offorce applicator 430 that may be surrounding anterior cusp 59. For otherapplications, force applicator 430 is adapted to be placed around all ora portion of anterior cusp 59, and not necessarily around any portion ofposterior cusp 56.

Reference is made to FIGS. 19A and 19B, which are schematicillustrations of mitral valve 58 before and after placement of forceapplicator 430, respectively, in accordance with an embodiment of thepresent invention. FIG. 19A shows mitral valve 58 during systole, priorto the placement of force applicator 430. Posterior cusp 56 and anteriorcusp 59 are slightly separated from one another, causing mitral valveregurgitation. FIG. 19B shows force applicator 430 placed aroundposterior cusp 56, and applying outward force (indicated by arrows 464)on a wall 468 of a heart chamber. Such outwardly-applied force drawscommissural cusps 78 away from one another, stretching mitral valve 58and thereby forcing posterior cusp 56 and anterior cusp 59 of mitralvalve 58 closer to one another, and thereby preventing regurgitation.(Broken lines 469 show the shape of annulus 60 prior to placement offorce applicator 430, for the sake of comparison with FIG. 19A.)

Reference is made to FIG. 20, which is a schematic illustration of aportion of force applicator 430 placed around a portion of posteriorcusp 56, in accordance with an embodiment of the present invention. Forsome applications, force applicator 430 is placed in the space definedby ventricular wall 70 of left ventricle 72, a ventricular surface ofposterior cusp 56 in a vicinity of annulus 60, and third-order chordaetendineae 74 (also called tertiary or basal chordae). (Third-orderchordae 74, of which only two of many are shown in the figure forclarity of illustration, originate directly from the trabeculae carneaeof ventricular wall 70, and attach to posterior cusp 56 in a vicinity ofannulus 60.) Alternatively or additionally, the space is defined bysecond-order chordae tendineae (not shown in the figure). Furtheralternatively, force applicator 430 is adapted to be placed in a leftatrium of the heart, in contact with or in a vicinity of mitral valve 58(configuration not shown).

Reference is made to FIGS. 21A and 21B, which are schematicillustrations of mitral valve 58 before and after expansion of forceapplicator 430, respectively, in accordance with an embodiment of thepresent invention. FIG. 21A shows mitral valve 58 during systole,immediately after placement of force applicator 430, but prior to theoutward expansion of the force applicator. Force applicator 430 isconfigured and placed such that there is a gap 490 between the forceapplicator and dilated wall 468 of the heart chamber. Posterior cusp 56and anterior cusp 59 are slightly separated from one another, causingmitral valve regurgitation. FIG. 21B shows force applicator 430 afteroutward expansion of ends 462 of the force applicator, as symbolicallyindicated by arrows 492. Such outwardly-applied force, in addition todrawing commissural cusps 78 away from one another, draws heart wall 468closer to force applicator 430 in a vicinity of gap 490. Such tighteningof wall 468 against force applicator 430 may occur immediately uponoutward expansion of force applicator 430, or may occur over time, e.g.,within about one month of expansion of force applicator 430, as theheart adapts to and heals because of the placement of the forceapplicator.

In an embodiment of the present invention, a surface of force applicator430 opposite heart wall 468 is configured to enhance fibrosis betweenthe force applicator and the heart wall. For example, the surface may beroughened, and/or coated with a fibrosis-enhancing substance. Thefibrosis holds tissue of the heart wall against the force applicator,thereby helping prevent future dilation of the heart. Thus, forceapplicator 430 actively changes the shape of the heart around the mitralvalve, and the fibrosis helps maintain this new shape.

Reference is mage to FIG. 22, which is a schematic illustration of aconfiguration of force applicator 430, in accordance with an embodimentof the present invention. In this configuration, force applicator 430comprises or is shaped to define one or more protruding extensions 94 atone or both ends 462 of the force applicator. The extensions increasethe outward pushing of the force applicator on the heart wall.

Reference is made to FIG. 23, which is a schematic illustration ofanother configuration of force applicator 430, in accordance with anembodiment of the present invention. In this configuration, forceapplicator 430 comprises or is shaped to define one or more couplingelements, which are adapted to hold the force applicator in place afterplacement. For some applications, the coupling elements comprise one ormore protrusions 496, oriented on the force applicator such that theprotrusions contact and grip the wall of the heart. Typically,protrusions 496 are positioned in a vicinity of ends 462 of forceapplicator 430, and/or along the length of the force applicator, such asin a vicinity of a middle of the force applicator. For someapplications, protrusions 496 are positioned at the ends of protectingextensions 494, described hereinabove with reference to FIG. 22(configuration not shown). For other applications, the coupling elementsare adapted to be coupled to the mitral valve, and/or to one or morechordae tendineae, such as third-order chordae tendineae 74, orsecond-order chordae tendineae (not shown in the figures). For theseapplications, the coupling elements may comprise, for example, hooks,sutures, or staples (configuration not shown).

Reference is made to FIG. 24, which is a schematic illustration of aprocedure for introducing force applicator 430 into heart 50 of asubject, in accordance with an embodiment of the present invention.Typically, force applicator 430 is introducing into ventricle 72 by acatheter 481, which is typically introduced into ventricle 72 viaascending aorta 82. A surgeon typically guides force applicator 430 to adesired location using images of heart 50 captured using techniquesknown in the art. Alternatively or additionally, the surgeon employs anechocardiogram to determine if placement of force applicator 430achieves closure of the mitral valve. For some applications, forceapplicator 430 is adjustable during placement, for example, as describedhereinbelow with reference to FIG. 26 and/or FIG. 27. For suchapplications, if the device does not sufficiently close the valve, thesurgeon may adjust the device in situ until the valve is sufficientlyclosed.

For some applications, force applicator 430 comprises, e.g., at a distalend thereof, one or more wireless position sensors, such as thosemanufactured by Biosense, Inc. (New Brunswick, N.J.), or otherwise knownin the art. Alternatively or additionally, force applicator 430comprises, e.g., at a distal end thereof, one or more sensors for aidingnavigation, such as an ultrasound sensor, an infrared sensor, or anoptical sensor. For some applications, force applicator 430 comprises asteering mechanism, such as those known in the art of coronary catheternavigation. For some applications, the surgeon magnetically navigatesforce applicator 430, such as using techniques described in U.S. Pat.Nos. 6,817,364 or 6,522,909 to Garibaldi et al., or U.S. Pat. No.6,475,223 to Werp et al., which are incorporated herein by reference,mutatis mutandis.

Reference is made to FIG. 25, which is a schematic illustration of adistal end 484 of catheter 481, in accordance with an embodiment of thepresent invention. In this embodiment, the distal end of catheter 481opens laterally, rather than at its end, so as to guide force applicator430 towards mitral valve 58 after the catheter is inserted into leftventricle 72.

Reference is made to FIG. 26, which is a schematic illustration of anadjustment mechanism 500 for force applicator 430, in accordance with anembodiment of the present invention. Adjustment mechanism 500 comprisesa center wheel 502, which is configured to move ends 462 of forceapplicator 430 closer and farther from one another, in a manner similarto a center wheel of a draftsman's compass.

Reference is made to FIG. 27, which is a schematic illustration ofanother adjustment mechanism 520 for force applicator 430, in accordancewith an embodiment of the present invention. Adjustment mechanism 520comprises one or more screws 522 in a vicinity of one or both ends 462of force applicator 430. Rotation of screws 522 in one directionincreases the pushing of end 462 into the heart wall, while rotation ofthe screws in the opposite direction decreases such pushing. For someapplications, force applicator 430 comprises both adjustment mechanism520 and adjustment mechanism 500, described hereinabove with referenceto FIG. 26.

It will be appreciated that wireless force applicator 430 has beengenerally described herein as comprising a single force applicator, thescope of the present invention is not limited to a single forceapplicator, and includes the use of multiple force applicators in seriesand/or parallel with one another.

It will be appreciated by persons skilled in the art that the presentinvention is not limited in what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1-29. (canceled)
 30. Apparatus for treating mitral valve regurgitation,comprising a band configured to be placed: around between 90 and 270degrees of a mitral valve of a heart, including around at least aportion of a posterior cusp of the valve, in a space defined by (a) aventricular wall, (b) a ventricular surface of the posterior cusp in avicinity of an annulus of the mitral valve, and (c) a plurality ofchordae tendineae of one or more types of chordae tendineae selectedfrom the group consisting of: second-order chordae tendineae andthird-order chordae tendineae, the band configured such that inflationthereof applies pressure to the posterior cusp.
 31. The apparatusaccording to claim 30, wherein the band is configured such thatinflation thereof holds the band in place.
 32. The apparatus accordingto claim 30, comprising a liquid for inflating the band, the liquidconfigured to at least partially solidify after inflation of the bandtherewith. 33-35. (canceled)
 36. The apparatus according to claim 30,further comprising: at least one stent, configured to be placed while ina contracted state around between 90 and 270 degrees of the mitral valveof a heart wherein the band is positioned within the stent, and whereinthe band is configured to expand the stent upon inflation, such that thestent applies pressure to the posterior cusp. 37-68. (canceled)
 69. Amethod for treating mitral valve regurgitation, comprising: inserting aband around between 90 and 270 degrees of a mitral valve of a heart,including around at least a portion of a posterior cusp of the valve, ina space defined by (a) a ventricular wall, (b) a ventricular surface ofthe posterior cusp in a vicinity of an annulus of the valve, and (c) aplurality of chordae tendineae of one or more types of chordae tendineaeselected from the group consisting of: second-order chordae tendineaeand third-order chordae tendineae; and applying pressure to theposterior cusp by inflating the band.
 70. The method according to claim69, wherein inflating the band comprises inflating the band so as tohold the band in place.
 71. The method according to claim 69, whereininflating the band comprises inflating the band with a liquid that atleast partially solidifies after inflation.
 72. The method according toclaim 69, wherein applying the pressure does not comprise couplingeither a distal or a proximal end of the band to any portion of theheart, other than by the inflating. 73-74. (canceled)
 75. The methodaccording to claim 69, wherein: inserting the band comprises insertingat least one stent in a contracted state around between 90 and 270degrees of the mitral valve of a heart, the band is positioned withinthe stent, and applying pressure to the posterior cusp comprisesapplying pressure to the posterior cusp by expanding the stent byinflating the band positioned within the stent.
 76. The method accordingto claim 75, wherein inserting the stent comprises coupling at least oneof a distal and a proximal end of the stent to at least one respectivechorda tendinea. 77-135. (canceled)
 136. The apparatus according toclaim 30, wherein the plurality of chordae tendineae includes thethird-order chordae tendineae.
 137. The apparatus according to claim 30,wherein the plurality of chordae tendineae includes the second-orderchordae tendineae.
 138. The apparatus according to claim 30, furthercomprising an external pressure source configured to inflate the band.139. The apparatus according to claim 30, wherein at least a portion ofthe band comprises an elastic material, configured to shorten a lengthof the band.
 140. The apparatus according to claim 30, wherein theplurality of chordae tendineae comprises at least a first chordatendinea and a second chorda tendinea, and wherein the apparatus furthercomprises distal and proximal coupling elements, coupled to the band atthe distal and proximal ends thereof, respectively, and configured to becoupled to the first chorda tendinea and the second chorda tendinea,respectively, each of the first and the second chordae tendineaeselected from the group consisting of: one of the third-order chordaetendineae, and a first-order chorda tendinea that inserts on acommissural cusp of the mitral valve.
 141. The apparatus according toclaim 140, wherein the distal and proximal coupling elements areconfigured to be coupled to the first and second chordae tendineae suchthat the band tightens the annulus of the valve.
 142. The apparatusaccording to claim 140, wherein the distal and proximal couplingelements comprise respective hooks, configured to be hooked to the firstand second chordae tendineae, respectively.
 143. The method according toclaim 69, wherein the plurality of chordae tendineae includes thethird-order chordae tendineae.
 144. The method according to claim 69,wherein the plurality of chordae tendineae includes the second-orderchordae tendineae.
 145. The method according to claim 69, whereininserting comprises inserting the band around no portion of an anteriorcusp of the valve.
 146. The method according to claim 69, whereininserting comprises inserting the band such that a first portion of theband surrounds the at least the portion of the posterior cusp and asecond portion of the band surrounds at least a portion of an anteriorcusp of the valve, and wherein a length of the first portion of the bandthat surrounds the at least the portion of the posterior cusp is atleast 5 times a total length of the second portion of the band thatsurrounds the at least the portion of the anterior cusp of the valve.147. The method according to claim 69, wherein at least a portion of theband includes an elastic material, configured to shorten a length of theband, and wherein coupling the band comprises coupling the bandincluding the elastic material.
 148. The method according to claim 69,wherein the plurality of chordae tendineae comprises at least a firstchorda tendinea and a second chorda tendinea, and wherein the methodfurther comprises coupling a distal end and a proximal end of the bandto the first chorda tendinea and the second chorda tendinea,respectively, each of the first and second chordae tendineae selectedfrom the group consisting of: one of the third-order chordae tendineae,and a first-order chorda tendinea that inserts on a commissural cusp ofthe mitral valve.
 149. The method according to claim 148, whereincoupling the distal end and the proximal end of the band to the firstchorda tendinea and the second chorda, respectively, comprisestightening the annulus of the valve.
 150. The method according to claim148, wherein coupling the distal end and the proximal end of the bandcomprises: coupling a distal coupling element at the distal end of theband to the first chorda tendinea; coupling a proximal coupling elementat the proximal end of the band to the second chorda tendinea.
 151. Themethod according to claim 150, wherein the distal and proximal couplingelements include respective hooks, and wherein coupling the distal andproximal coupling element comprises hooking the distal and proximalcoupling elements to the first and second chordae tendineae,respectively.